JP4576741B2 - Piezoelectric oscillator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a piezoelectric oscillator, and in particular, a piezoelectric oscillator having a configuration in which a piezoelectric vibrator packaged using a pillar member is fixed on an upper part of a wiring board on which electronic components constituting an oscillation circuit and a temperature compensation circuit are mounted. It relates to the manufacturing method.
[0002]
[Prior art]
Due to the rapid progress of price reduction and miniaturization with the spread of mobile communication devices such as mobile phones, the price, size and thickness of piezoelectric oscillators such as crystal oscillators used in these communication devices are also reduced. There is a growing demand for conversion.
Therefore, conventionally, piezoelectric oscillators packaged using chip components have been manufactured, and the structure is such that a pillar member is provided on the upper part of a wiring board on which electronic components constituting an oscillation circuit and a temperature compensation circuit are mounted. There are many structures that fix the piezoelectric vibrators that are packaged using, and on the land on the wiring board on which the electronic components are mounted, cream solder is screen printed and the chip components are fixed by reflow method, and packaged The occupied area is reduced by three-dimensionally arranging the piezoelectric vibrator thus formed on the pillar member fixed to the wiring board.
[0003]
FIG. 3 shows a first external structure of a crystal oscillator which is an example of a conventional piezoelectric oscillator. This figure is a longitudinal cross-sectional view, in which a plurality of electronic components 2 constituting an oscillation circuit and a temperature compensation circuit are mounted on a land 1 on the upper surface, and a flat wiring board 4 having an external electrode 3 and the wiring A crystal oscillator including a crystal resonator 6 fixed with a predetermined gap through a pillar member 5 fixed to the upper surface of the substrate 4. Further, the bottom electrode 7 of the column member 5 is electrically and mechanically fixed to a column member fixing pattern 8 formed on the upper surface of the wiring board 4, and the upper electrode 9 of the column member 5 is connected to the bottom electrode 10 of the crystal resonator 6. It is fixed electrically and mechanically. The column member 5 used here is a rectangular column or other polygonal column ceramic block, a bottom electrode 7 provided on the bottom of the ceramic block, an upper electrode 9 provided on the top of the ceramic block, and a gap between the two electrodes. And a connecting conductor that conducts.
[0004]
When the pillar member 5 is fixed on the pillar member fixing pattern 8 on the wiring substrate 4, reflow connection is performed using cream solder applied on the pillar member fixing pattern 8 by screen printing. In this screen printing, cream solder is applied to the lands 1 at the same time. After placing the electronic components 2 and the column members 5 on the lands 1 and the column member fixing patterns 8 to which the cream solder is applied, The electronic component 2 and the column member 5 are fixed by simultaneously heating in the reflow furnace and then cooling.
As for the crystal unit 6, the column member 5 may be fixed on the wiring substrate 4, and the bottom electrode 10 may be fixed on the upper electrode 9 of the column member 5 using a conductive adhesive or the like. The connection between the electrode 9 and the bottom electrode 10 may be performed simultaneously with the reflow connection of the electronic component 2 or the like.
[0005]
FIG. 4 shows a second external structure of a crystal oscillator which is an example of a conventional piezoelectric oscillator. The difference between this conventional example and FIG. 3 is that a metal ball is used in this conventional example as the material of the column member that electrically and mechanically fixes the wiring board and the crystal resonator. Therefore, FIG. 4 shows an example in which the pillar member fixing pattern 8 on the wiring board 4 and the bottom electrode 10 of the crystal resonator 6 are connected using the pillar member 11 made of a metal ball. The connection between the column member 5 and the column member fixing pattern 8 and the connection method between the column member 5 and the bottom electrode 10 of the crystal resonator 6 may be reflow connection using cream solder, A connection using a conductive adhesive may also be used.
[0006]
[Problems to be solved by the invention]
However, the conventional piezoelectric oscillator has the following problems.
The crystal oscillator shown in FIG. 3 uses a prismatic column member 5, and when this column member 5 is fixed on the column member fixing pattern 8 of the wiring board 4, it is for column member fixing by screen printing. Reflow connection using cream solder applied on the pattern 8 is performed. Therefore, when placing the column member 5 on the cream solder of the column member fixing pattern 8, it is necessary to always place the column member 5 so that the electrode surface of the column member 5 is correctly in contact with the column member fixing pattern 8 surface. Conventionally, there is a risk that the electrode surface of the column member 5 is erroneously placed in a direction that does not contact the surface of the column member fixing pattern 8.
[0007]
FIG. 5 shows an external structure when a conventional square column member is attached to a wiring board. In the column member, electrodes 12 are provided on the upper and lower surfaces of a material such as ceramic, and the electrodes on the upper and lower surfaces are electrically connected by a through hole 13 or the like. When this column member is attached to the wiring board, as shown in (a) of the figure, the column member needs to have the electrodes 12 positioned on the upper surface and the lower surface, and both sides of the column member as shown in (b). If the electrode 12 is positioned on the board, the continuity between the wiring board and the crystal oscillator cannot be obtained when the crystal oscillator is attached to the column member.
In addition, there are some manufacturing errors in the dimensions of the column members, and when the crystal unit is fixed using the column members, the height dimensions of the column members vary, and there is a problem in the electromechanical fixing. May occur.
[0008]
On the other hand, the crystal oscillator shown in FIG. 4 uses a metal ball column member 5, and when this column member 5 is fixed on the column member fixing pattern 8 of the wiring board 4, The connection between the column member fixing pattern 8 and the connection between the column member 5 and the bottom electrode 10 of the crystal resonator 6 are performed by reflow connection using cream solder, respectively. When placed on the wiring board, there is a possibility that it is displaced from the column member fixing pattern 8 provided on the wiring board, which causes a problem that workability is lowered.
The present invention has been made in order to solve the problems that occur during the manufacture of the conventional piezoelectric oscillator as described above, and has improved the column member that electrically and mechanically fixes the wiring board and the piezoelectric vibrator. Accordingly, an object of the present invention is to provide a piezoelectric oscillator having high reliability and excellent work efficiency.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a piezoelectric oscillator according to the present invention has the following configuration. The piezoelectric oscillator according to the present invention is a piezoelectric device in which at least an electronic component constituting an oscillation circuit is mounted on a top surface and a planar wiring board having an external electrode on the bottom surface and a piezoelectric vibrator are conductively fixed via a column member. In the oscillator, the pillar member has a cut surface on a side surface and a metal surface electrically connected to each other on a top surface and a bottom surface, and the wiring board has the top surface on the bottom surface side of the pillar member. A pillar member fixing pattern for electrically fixing a metal surface is formed, and the piezoelectric vibrator is formed by sealing a piezoelectric vibration element in an airtight space of a package, and the pillar is provided on a bottom surface of the package. A bottom electrode for electrically connecting and fixing the metal surface on the upper surface side of the member is provided, and the metal surface on the upper surface side of the column member is electrically connected to the bottom electrode of the piezoelectric vibrator via a conductive member. Fixed and said pillar The metal surface on the bottom side of the material is conductively fixed to the column member fixing pattern through a conductive member, and the cut surface of the side surface of the column member is cut by fixing the column member to the wiring board. It is a formed surface .
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on illustrated embodiments.
1A and 1B are a longitudinal sectional view and an exploded perspective view of a crystal oscillator which is an example of a piezoelectric oscillator according to the present invention.
In the figure, a plurality of electronic components 15 constituting an oscillation circuit and a temperature compensation circuit are mounted on a land 14 on the upper surface, and a wiring board 17 provided with external electrodes 16 and a column member fixed to the upper surface of the wiring board 17. The crystal oscillator includes a crystal unit 19 fixed with a predetermined gap through 18. Further, the bottom electrode (bottom side electrode) 20 of the column member 18 is electrically and mechanically fixed to the column member fixing pattern 21 formed on the upper surface of the wiring board 17, and the upper electrode (upper surface side electrode) 22 of the column member 18. Is electrically and mechanically fixed to the bottom electrode 23 of the crystal unit 19. The column member 18 used here will be described in detail later, but is formed by forming a plurality of holes in the same ceramic plate, the thickness of the ceramic plate being the height direction of the column member, and wiring The thickness exceeds the maximum mounting height of the electronic component 15 mounted on the substrate 17. The column member 18 includes a bottom electrode 20 provided on the back surface of the ceramic plate, an upper electrode 22 provided on the surface of the ceramic plate, and a connection conductor that conducts between the electrodes.
For the crystal resonator 19, the column member 18 is fixed on the wiring substrate 17, and the bottom electrode 23 is fixed on the upper electrode 22 of the column member 19 using a conductive adhesive or the like.
[0013]
FIG. 2 is a diagram showing a method for manufacturing a wiring board and a column member and a method for joining and fixing the crystal oscillator as an example of the piezoelectric oscillator according to the present invention.
As shown in the figure, the printed circuit board 24 for the wiring board and the ceramic board 25 for the pillar member are divided into the wiring board 17 and the pillar member block 26 which are partitioned and formed on the large-area wiring board base material and the pillar member base material, respectively. Many are provided.
Here, the column member block 26 includes a lattice-shaped member that indicates a partition by forming a hole in the ceramic plate 25 for the column member, and a column member 18 that protrudes from the lattice-shaped member into a hole as a peninsular projection piece. It is formed integrally. Each column member 18 is arranged in accordance with the position of the column member fixing pattern 21 provided on the wiring board 17. The ceramic plate 25 for column members is metallized on the front and back surfaces, and a through hole or the like is provided at a predetermined position of the column member 18 to connect the front and back surfaces. An upper electrode is formed. Further, the thickness of the pillar member ceramic plate 25 is determined in accordance with the mounting height of the electronic component 15 mounted on the wiring board 17.
[0014]
Therefore, a description will be given of a method for bonding and fixing a wiring board and a pillar member of a crystal oscillator. First, after manufacturing a printed circuit board 24 for a wiring board having a wiring board formed by partitioning on a large-area wiring board base material, After soldering cream solder on the lands on which the electronic components 15 are mounted by screen printing and placing each electronic component 15, the electronic component 15 is fixed by heating in a reflow furnace and then cooling. Next, the pillar member ceramic plate 25 having the pillar member blocks 26 partitioned by providing predetermined holes on the pillar member base material is manufactured, and the electronic component 15 is mounted and fixed on the wiring. After the conductive adhesive is applied to the column member fixing patterns 21 provided on the respective wiring board blocks 26 of the printed circuit board 24 for the substrate, the column member fixing patterns 21 and the column members 18 are aligned, and wiring is performed. The printed board 24 and the pillar member ceramic board 25 are joined and fixed. Thereafter, the wiring board 17 to which the column member 18 is fixed is separated by cutting with a cutting machine such as a dicing saw at a position illustrated by a dotted line on the printed wiring board 24.
[0015]
As for the joining procedure of the printed circuit board 24 for the wiring board and the ceramic board 25 for the pillar member, first, the pillar member fixing pattern 21 first provided on the printed wiring board 24 for the wiring board and the pillar provided on the ceramic board 25 for the pillar member. After fixing the bottom electrode of the member 18 with a conductive adhesive or the like, cream solder is applied by screen printing to the lands 14 on which the electronic components 15 provided on the printed circuit board 24 are mounted. After placing 15, the electronic component 15 may be fixed by heating in a reflow furnace and then cooling.
[0016]
Further, regarding the joining procedure of the printed circuit board 24 for the wiring board and the ceramic board 25 for the pillar member, screen printing is performed on the land on which the electronic component 15 provided on the printed board 24 for the wiring board is mounted and the pattern 21 for fixing the pillar member. By applying cream solder and placing each electronic component 15, the printed circuit board 24 for the wiring board and the ceramic board 25 for the pillar member are aligned, heated in a reflow furnace, and then cooled. Thus, the electronic component 15 and the column member 18 provided on the column member ceramic plate 25 may be fixed.
[0017]
Therefore, since the pillar member according to the present invention is manufactured by forming a plurality of pillar members on one pillar member ceramic plate, the height of the pillar members is all the same, and when the piezoelectric vibrator is attached, It is possible to prevent a mounting failure due to a defective dimension of the pillar member, and a pillar member block that is partitioned on a large-area column member base material and a wiring that is partitioned and formed on a printed board for a large-area wiring board Since the substrates can be bonded together, efficient production becomes possible.
[0018]
In addition, by using the pillar member block formed on the base material for the pillar member having a large area, it is not necessary to individually place the pillar member on the pillar member fixing pattern provided on the wiring board. The vertical positional relationship required when placing the pole is always in the same direction, preventing incorrect mounting of the pillar member, and fixing the pillar member provided on the wiring board when the pillar member is placed on the cream solder There is no possibility of deviating from the work pattern, and work efficiency is improved.
Next, when the manufacture of the wiring board 17 to which the column member 18 is fixed is completed, a conductive adhesive is applied to the upper electrode 22 of the column member 18 and adhered to the bottom electrode 23 of the crystal resonator 19, thereby crystal oscillation. The quartz oscillator is completed by fixing the child 19 to the wiring board 17.
[0019]
【The invention's effect】
As described above, the present invention provides a piezoelectric oscillator having a configuration in which a packaged piezoelectric vibrator is fixed on an upper part of a wiring board. As a pillar member to be fixed, a pillar member provided on a pillar member block partitioned on a large-area pillar member base material is used, and wiring formed by partitioning the pillar member and a large-area wiring board base material Since the substrates are bonded together, reliability and production efficiency are improved when assembling the piezoelectric oscillator, and a significant effect can be achieved in reducing the cost of the piezoelectric oscillator.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view (a) and an exploded perspective view (b) of a crystal oscillator which is an example of a piezoelectric oscillator according to the present invention.
FIG. 2 is a diagram showing a method for manufacturing a wiring board and a column member and a method for joining and fixing the crystal oscillator as an embodiment of the piezoelectric oscillator according to the present invention.
FIG. 3 shows a first external structure of a crystal oscillator which is an example of a conventional piezoelectric oscillator.
FIG. 4 shows a second external structure of a crystal oscillator which is an example of a conventional piezoelectric oscillator.
FIG. 5 shows an external structure when a conventional square column member is attached to a wiring board.
[Explanation of symbols]
1 .... Land, 2 .... Electronic parts,
3 .... external electrode, 4 .... wiring board,
5 .... Pillar member, 6 .... Quartz crystal,
7 .... Bottom electrode, 8 .... Pattern fixing pattern,
9 .... Upper electrode, 10 .... Bottom electrode,
11 .. Column member, 12 .... Electrode,
13 · Through hole, 14 · Land,
15 .... Electronic parts, 16 .... External electrode,
17 .... Wiring board, 18 .... Pillar member,
19 .. Quartz crystal, 20 .. Bottom electrode,
21 .... Pattern fixing pattern, 22 .... Upper electrode,
23 .. Bottom electrode 24 .. Printed circuit board for wiring board,
25. ・ Ceramic plate for pillar member, 26 ・ ・ Column member block

Claims (1)

A piezoelectric oscillator in which at least an electronic component constituting an oscillation circuit is mounted on a top surface and a planar wiring board having an external electrode on a bottom surface and a piezoelectric vibrator are conductively fixed via a pillar member,
The column member has a cut surface on the side surface and a metal surface that is electrically connected to each other on the top surface and the bottom surface,
The wiring board is formed with a column member fixing pattern for conductively fixing the metal surface on the bottom side of the column member on the upper surface thereof,
The piezoelectric vibrator is obtained by sealing a piezoelectric vibration element in an airtight space of a package, and has a bottom electrode for conductively fixing the metal surface on the upper surface side of the pillar member on the bottom surface of the package. Yes,
The metal surface on the upper surface side of the column member is conductively fixed to the bottom electrode of the piezoelectric vibrator via a conductive member,
The metal surface on the bottom side of the column member is conductively fixed to the column member fixing pattern via a conductive member,
The piezoelectric oscillator according to claim 1, wherein the cut surface of the side surface of the column member is a surface formed by cutting after fixing the column member to the wiring board .

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